Metal-insulator-metal (MIM) capacitor structure and method for forming the same

Abstract

A metal-insulator-metal (MIM) capacitor structure and a method for forming the same are provided. The MIM capacitor structure includes a substrate, and the substrate includes a capacitor region and a non-capacitor region. The MIM capacitor structure includes a first electrode layer formed over the substrate, and a first spacer formed on a sidewall of the first electrode layer. The MIM capacitor structure includes a first dielectric layer formed on the first spacers, and a second electrode layer formed on the first dielectric layer. The second electrode layer extends from the capacitor region to the non-capacitor region, and the second electrode layer extends beyond an outer sidewall of the first spacer.

What is claimed is: 
     
       1. A metal-insulator-metal (MIM) capacitor structure, comprising:
 a substrate, wherein the substrate comprises a capacitor region and a non-capacitor region; 
 a first electrode layer formed over the substrate; 
 a first spacer formed on a sidewall of the first electrode layer; 
 a first dielectric layer formed on the first spacers, wherein the first dielectric layer has a top portion and a bottom portion lower than the top portion, the top portion is in direct contact with a top surface of the first electrode layer, and the bottom portion is in direct contact with an outer sidewall of the first spacer; 
 a second electrode layer formed on the first dielectric layer, wherein the second electrode layer extends from the capacitor region to the non-capacitor region, and the second electrode layer extends beyond the outer sidewall of the first spacer; and 
 a second spacer and a third spacer formed on opposite sidewalls of the second electrode layer, wherein a top surface of the second spacer is higher than a top surface of the third spacer. 
 
     
     
       2. The MIM capacitor structure as claimed in  claim 1 , wherein the first dielectric layer extends from the capacitor region to the non-capacitor region. 
     
     
       3. The MIM capacitor structure as claimed in  claim 1 , wherein the first dielectric layer has a first dielectric constant, and the first spacer has a second dielectric constant that is lower than the first dielectric constant. 
     
     
       4. The MIM capacitor structure as claimed in  claim 1 , further comprising:
 a redistribution layer (RDL) structure formed over the second electrode layer, wherein the RDL structure passes through the second electrode layer. 
 
     
     
       5. The MIM capacitor structure as claimed in  claim 1 , further comprising:
 a second dielectric layer formed on the second spacer; and 
 a third electrode layer formed on the second dielectric layer, wherein the second spacer is between the second electrode layer and the third electrode layer. 
 
     
     
       6. The MIM capacitor structure as claimed in  claim 5 , wherein the third electrode layer extends from the capacitor region to the non-capacitor region and extends beyond an outer sidewall of the second spacer. 
     
     
       7. The MIM capacitor structure as claimed in  claim 1 , further comprising:
 a redistribution layer (RDL) structure passing through the first electrode layer, wherein the RDL structure comprises a barrier layer, and the first electrode layer is in direct contact with the barrier layer. 
 
     
     
       8. The MIM capacitor structure as claimed in  claim 1 , further comprising:
 a second dielectric layer formed on the third spacer, wherein a sidewall of the third spacer is covered by the second dielectric layer. 
 
     
     
       9. The MIM capacitor structure as claimed in  claim 1 , wherein the first spacer has a tapered width from a bottom surface to a top surface. 
     
     
       10. A metal-insulator-metal (MIM) capacitor structure, comprising:
 a first electrode layer formed over a substrate; 
 a first dielectric layer formed on the first electrode layer; 
 a first spacer formed on a sidewall of the first electrode layer and a sidewall of the first dielectric layer; and 
 a second electrode layer formed on the first spacer and the first dielectric layer, wherein the first spacer is in direct contact with the second electrode layer. 
 
     
     
       11. The MIM capacitor structure as claimed in  claim 10 , wherein the substrate comprises a capacitor region and a non-capacitor region, and the first dielectric layer extends from the capacitor region to the non-capacitor region. 
     
     
       12. The MIM capacitor structure as claimed in  claim 10 , wherein the first spacer has a height which is a sum of a height of the first electrode layer and a height of the first dielectric layer. 
     
     
       13. The MIM capacitor structure as claimed in  claim 10 , further comprising:
 a redistribution layer (RDL) structure formed over the second electrode layer, wherein the RDL structure passes through the second electrode layer. 
 
     
     
       14. The MIM capacitor structure as claimed in  claim 10 , further comprising:
 a second spacer formed on a sidewall of the second electrode layer; 
 a second dielectric layer formed on the second spacer; and 
 a third electrode layer formed on the second dielectric layer, wherein the second spacer is between the second electrode layer and the third electrode layer. 
 
     
     
       15. The MIM capacitor structure as claimed in  claim 10 , further comprising:
 a second spacer and a third spacer formed on opposite sidewalls of the second electrode layer, wherein a top surface of the second spacer is higher than a top surface of the third spacer. 
 
     
     
       16. The MIM capacitor structure as claimed in  claim 10 , wherein the first spacer has a tapered width from a bottom surface to a top surface. 
     
     
       17. A method for forming a metal-insulator-metal (MIM) capacitor structure, comprising:
 forming a first electrode layer over a substrate; 
 forming a first dielectric layer on the first electrode layer; 
 forming a first spacer on a sidewall of the first electrode layer and a sidewall of the first dielectric layer; and 
 forming a second electrode layer on the first dielectric layer and the first spacer, wherein the first spacer is in direct contact with the second electrode layer. 
 
     
     
       18. The method for forming a MIM capacitor structure as claimed in  claim 17 , further comprising:
 patterning the first dielectric layer and the first electrode layer before forming the first spacer on the sidewall of the first electrode layer. 
 
     
     
       19. The method for forming a MIM capacitor structure as claimed in  claim 17 , further comprising:
 forming a second dielectric layer on the second electrode layer; 
 forming a second spacer on a sidewall of the second electrode layer and a sidewall of the second dielectric layer; and 
 forming a third electrode layer on the second dielectric layer. 
 
     
     
       20. The method for forming a MIM capacitor structure as claimed in  claim 17 , further comprising:
 forming a redistribution layer (RDL) structure over the second electrode layer, wherein the RDL structure passes through the second electrode layer.